This invention relates to the field of processing citrus fruit, and more particularly, this invention relates to the field of processing citrus fruit and facilitating oil recovery versus juice yield.
Oil recovery versus juice yield is becoming an increasingly important aspect of citrus fruit processing. Many factors go into the processing of citrus fruit, including the use of much water, the removal of trash, black mold, pesticides and other matter from the surface of the fruit, and other factors. One proposed method uses a vegetable peeler with an elongate auger and abrasive rollers to remove all the oil from the citrus fruit by removing a substantial amount of the surface. However, this process does not maintain peel integrity and is not advantageous for many types of citrus fruit processing, such as oranges.
The present invention now allows for the processing of citrus fruit, such as oranges or grapefruit, and also provides a pre-wash, while recovering oil before juice extraction in an amount sufficient to remove a majority of the oil within the citrus fruit while leaving sufficient peel thickness for maintaining peel integrity.
In accordance with the present invention, the method and system allows for the processing of citrus fruit, such as oranges and grapefruit, with enhanced oil recovery versus juice yield. A peeling chamber has two opposing ends and sides. A fruit inlet and fruit outlet are formed at respective ends. A plurality of abrasive rollers are rotatably mounted in an arcuate configuration within the peeling chamber at an area forming a lower portion of the peeling chamber. Citrus fruit is fed into the fruit inlet and through the peeling chamber and out from the fruit outlet. The citrus fruit engages against the rotating abrasive rollers. The residence time of the fruit within the chamber allows for the peeling off of the outer surface of the fruit in an amount sufficient to remove a majority of the oil within the citrus fruit, but leaving sufficient peel thickness for maintaining peel integrity.
It was found through much experimentation that the method and system is operable best when the abrasive rollers are stainless steel and have a knurl cut with peaks of about 0.050 inches. Water is sprayed within the peeling chamber against the citrus fruit and substantially along the interior of the peeling chamber as the citrus fruit is fed through the peeling chamber. The water is sprayed from water spray nozzles positioned along both sides of the peeling chamber interior for ensuring that oil is washed down with the sprayed water as an emulsion. The citrus fruit is fed through the peeling chamber by rotating a feed auger that extends longitudinally through the peeling chamber from the inlet to the outlet. The feed auger is typically rotated in a direction opposite to the rotation direction of the feed auger to force the fruit downward against the abrasive rollers.
In yet another aspect of the present invention, the oil concentration is measured within the oil emulsion as it exits the peeling chamber and one of the at least residence time of the fruit within the peeling chamber, the rotation speed of the abrasive rollers, or the amount of water sprayed onto the citrus fruit is adjusted.
The fruit is advanced from the peeling chamber into a juice extractor for extracting juice and oil from the citrus fruit. The oil concentration of the fruit juice received from the extractor is monitored and at least one of the residence time of the fruit within the peeling chamber, the rotation speed of the abrasive rollers, the amount of water sprayed onto the citrus fruit within the peeling chamber, or the amount of water used by the juice extractor is adjusted in response to a measured oil concentration that is not within a predetermined range. It is also possible to adjust the amount of fruit that is fed into the peeling chamber based on the measured oil concentration, such as by adjusting the feed of the fruit into the peeling chamber.
After the fruit passes through the peeling chamber, the surface of the citrus fruit is scanned for determining the peel integrity and also determining the quantity of fruit that has been processed out of the peeling chamber. Based upon this scanned surface, at least one of the residence time of fruit within the peeling chamber, the rotation speed of the abrasive rollers, the amount of water sprayed onto the citrus fruit, or the amount of water used by the extractor in response to a measured peel deviation can be adjusted. In yet another aspect of the present invention, it is possible to adjust the quantity of fruit fed into the peeling chamber.